Society of Radiologists in Ultrasound response to 'Proposed simplified protocol for initial assessment of endometriosis with transvaginal ultrasound'

Society of Radiologists in Ultrasound response to ‘Proposed simplified protocol for initial assessment of endometriosis with transvaginal ultrasound’ Abstract Linked article: This Correspondence comments on Deslandes and Leonardi. Click here to view the article. We read with interest the recent opinion piece, ‘Proposed simplified protocol for initial assessment of endometriosis with transvaginal ultrasound’ by Deslandes and Leonardi in Ultrasound in Obstetrics and Gynecology, which highlights the need for accessible non-invasive imaging for endometriosis1. As the authors of the recently published multidisciplinary expert consensus statement, entitled ‘Society of Radiologists in Ultrasound consensus on routine pelvic US for endometriosis’, published in April 2024 in Radiology2, we value efforts that amplify exposure to this important topic. It is reassuring that many of the opinions presented by the authors closely mirror those of our peer-reviewed consensus, which was developed through an evidence-based, systematic literature review and a modified Delphi technique. This consensus involved: radiologists; gynecologists; minimally invasive gynecologic and infertility surgeons; stakeholders from major North American radiology, ultrasound, gynecological surgery and infertility societies; the American Institute of Ultrasound in Medicine (AIUM) and American College of Radiology (ACR) representatives of the current multidisciplinary guideline for female pelvic ultrasound3; and community radiologists and sonographers. Both the Society of Radiologists in Ultrasound (SRU) consensus statement2 and the opinion article of Deslandes and Leonardi1 share the goal of improving the detection of endometriosis during initial ultrasound examinations by incorporating the uterine sliding sign and examining the posterior compartment for deep endometriosis (DE) nodules on the uterosacral ligaments and adjacent rectosigmoid colon. This approach enables the opportune detection of endometriosis at these sites, which are frequently involved in DE and are easily visualized by transvaginal ultrasound. The opinion article of Deslandes and Leonardi1 acknowledges the SRU consensus statement and raises concerns regarding the inclusion of indirect observations of endometriosis without providing supporting references. In North America, most ultrasound examinations are performed by sonographers and interpreted by radiologists, neither of whom is specialized in endometriosis, and they provide non-specialized head-to-toe ultrasound imaging. In these circumstances, raising awareness of potential endometriosis findings during routine ultrasound examination can expedite patient triage. Most patients with pelvic complaints undergo ultrasound as their initial imaging test, so it is crucial that endometriosis is considered during these evaluations. The SRU expert panel introduced the terms ‘direct’ and ‘indirect’ observations to ensure that indirect signs of endometriosis, often seen during routine pelvic sonography, are recognized. These signs represent the fibrosis and tissue distortion typically associated with endometriosis. The panel agreed that the term ‘indirect observations’ is more comprehensive and descriptive than the term ‘soft markers’. The SRU consensus emphasizes observing multiple indirect or associated findings to highlight the potential for endometriosis, even when direct observations, such as uterosacral ligament, rectosigmoid or ovarian endometriosis involvement, are not apparent. Notably, ovarian endometriomas can be suppressed in patients on oral contraceptives, leading to a potential pitfall of missed diagnosis4. Indirect signs of endometriosis, or ‘soft markers’, were considered by the consensus participants as being essential to assess for endometriosis, especially during early patient triage, to prevent premature dismissal of care2. Ignoring these signs could delay diagnosis for patients without direct imaging evidence of endometriosis on routine pelvic ultrasound examination. When patients are properly triaged, they can undergo more advanced imaging, such as ultrasound with bowel preparation or magnetic resonance imaging (MRI), based on local expertise and resources5. This approach helps expedite diagnosis, reducing the typical 7–10-year delay from onset of symptoms to diagnosis. Failing to take into account these indirect features, as Deslandes and Leonardi suggest1, risks missing cases of endometriosis. While Deslandes and Leonardi are clearly passionate about endometriosis imaging, many of the specifics of their proposal1 have been considered previously in the literature. Implementation of direct posterior compartment imaging and the uterine sliding sign during routine outpatient ultrasound examination without special preparation has demonstrated the efficacy of combining direct and indirect observations. Cine clips identify DE and may be utilized to refer patients for advanced imaging, such as ultrasound with bowel preparation or endometriosis-specific MRI. This approach achieved sensitivity and specificity of 68% and 98%, respectively6, as Deslandes and Leonardi cite. A few more critiques of the SRU consensus statement by Deslandes and Leonardi1 also deserve comment. They assert that the SRU protocol fails to evaluate systematically common locations of DE. On the contrary, the SRU protocol includes standardized transverse and longitudinal cine clips that cover these areas of high frequency of endometriosis3. They also mention the ‘uncertainty’ of sonographers regarding the optional addition of ovarian mobility maneuvers, without supporting references. The SRU consensus defines minimum imaging requirements and highlights additional optional maneuvers that can be performed by centers ready to go above and beyond, with the overarching goal of expediting endometriosis diagnosis by making imaging easily implementable by imagers and readily accessible to a larger patient population. Often, coexisting pathologies or patient pain points guide additional scanning, and a rigid protocol, as proposed by Deslandes and Leonardi, risks creating tunnel vision, reducing the flexibility needed for optimal patient care. The SRU panel recommended expanding existing protocols to include imaging of the uterosacral ligaments and mid-to-upper rectum using wide-field-of-view cine clips of the posterior cul-de-sac. This approach is feasible even in basic imaging settings, requires minimal additional acquisition time, and involves little extra training, as many labs already acquire similar cine clips. When approaching a potentially sweeping change in the practice of female pelvic ultrasound, the SRU panel paid careful attention to voices outside academic imaging practices, including radiologists and sonographers in community settings. There are over 82 000 sonographers in the USA7, and the SRU expert panel recognized that training sonographers to reliably identify normal uterosacral ligaments would present an unreasonable learning curve and time burden, while cine clips of the posterior cul-de-sac are within the current scope of their practice8-10. Concurrently, SRU panel members are actively pursuing educational efforts with the Society of Diagnostic Medical Sonography in the USA. In conclusion, both the SRU consensus statement2 and the opinion article of Deslandes and Leonardi1 aim to reduce diagnostic delays for endometriosis. Neither proposal replaces the need for a comprehensive preoperative assessment using either comprehensive ultrasound or endometriosis-specific MRI interpreted by experts11. The Deslandes and Leonardi proposal1 represents a potential adaptation of the SRU consensus statement. Their criticisms, particularly regarding indirect observations and ovarian immobility, would benefit from the inclusion of supporting references and details addressing the challenges and opportunities of North American imaging centers. While Deslandes and Leonardi represent endometriosis-focused centers, aiming to achieve detailed mapping of endometriosis in a specialized setting, the SRU consensus statement is designed for broader application even in non-specialized practices, helping to triage patients with concerning symptoms to optimal imaging and clinical management. These patients have borne the cost of their studies being interpreted as ‘normal’ or negative for years. This is our chance to change things, and expedite diagnosis for endometriosis at the initial imaging study, even when this is done without special preparation. The strength of the SRU consensus lies in its evidence-based approach, statistically derived consensus between endometriosis experts, and ease of implementation and practical application in routine ultrasound settings, with the goal of reducing diagnostic delays for endometriosis patients. Disclosures S.W.Y. was a sponsored speaker for the American Association of Gynecologic Laparoscopists and the XI Lapanatomy Symposium on Anatomy and Advanced Pelvic Surgery. W.V. is owner and founder of the International Endometriosis Imaging Congress and was a sponsored speaker for the American Association of Gynecological Laparoscopists, American Society of Reproductive Medicine, American Roentgen Ray Society, Society for Advanced Body Imaging, World Congress on Endometriosis, Society of Diagnostic Medical Sonography and Society for Women's Health Research. P.J. was a sponsored speaker for the World Class CME and American Roentgen Ray Society. S.R. receives book royalties from Elsevier. R.K. was a sponsored speaker for Sumitomo Pharmacy. Y.G. is a consultant for GE Healthcare. T.B. was a sponsored speaker for Symposia Medicus. DATA AVAILABILITY STATEMENT Data sharing is not applicable to this article as no new data were created or analyzed in this study.